[3dem] 3dem Digest, Vol 142, Issue 60

[Carlos Oscar S. Sorzano]

Thank you, Anchi, for making the experimental connection of why the 
signal drops at high frequency below the level of noise (beside the fact 
that macromolecules have less energy at high frequency than low).

Kind regards, Carlos Oscar

El 27/06/2019 a las 17:24, Anchi Cheng escribió:
> Hi, Mohamed,
>
> Just want to answer the first part of your first question.
>
> Even though the signal you get in super-resolution mode is real, it is very dampened by DQE
> of the detector.  Let’s say you have a signal count of 100 above the background across all frequency.
> If DQE at your detector pixel limit is 0.2, and at 0.8 at zero frequency.  The output of that signal to
> your image becomes 100*0.2 = 20 in the former and 80 in the latter.  This only gets worse as
> you go into super-resolution frequency.
>
> Since protein or other biomolecule do not give strong signal at high resolution to start with,
> my “signal across all frequency” assumption above is already false.  You can see that information
> get through to your image at high frequency is much lower in reality.
>
> If your 1Å pixel data does not give reconstruction resolution to 85% Nyquist resolution (2.35 Å resolution
> for 1 Å pixel) with all the modern single-particle processing tricks, the problem is in the specimen.  The very
> dampened signal in the super resolution range by unbinning your images is not going to help you.
>
>> 1-  Will my resolution improve if I do not apply bining?
> Best,
>
> Anchi Cheng
> NYSBC
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-- 
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Carlos Oscar Sánchez Sorzano                  e-mail:   coss at cnb.csic.es
Biocomputing unit                             http://i2pc.es/coss
National Center of Biotechnology (CSIC)
c/Darwin, 3
Campus Universidad Autónoma (Cantoblanco)     Tlf: 34-91-585 4510
28049 MADRID (SPAIN)                          Fax: 34-91-585 4506
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